This application is based on the application No. 2001-385801 filed in Japan, the content of which is incorporated hereinto by reference.
1. Field of the Invention
The present invention relates to an electric circuit unit for connecting a plurality of circuit boards to one another. This electric circuit unit is widely used for an information processing unit such as a computer, an electric/optical information communication unit, an image display unit, or the like.
2. Description of Related Art
A connector or cable is conventionally used for connecting a plurality of circuit boards to one another.
In the inter-board connection structure of the type above-mentioned, a signal processing function cannot be given to the connection structure such as a connector or cable by mounting electronic/electric circuit elements and/or optical circuit elements on the connection structure itself.
There has been proposed an example in which a plurality of parallel boards are connected to one another with a board disposed at right angles thereto (Japanese Patent Laid-Open Publication No. H6-120636).
To provide this orthogonal board with a signal processing function, electronic/electric circuit elements and/or optical circuit elements can be disposed thereon. However, since discrete elements are mounted on the board, the mounting density is lowered to prevent the whole electric circuit unit from being made in a compact design.
According to the present invention, an electric circuit unit uses apart (hereinafter referred to as xe2x80x9cmodulexe2x80x9d) formed by resin-molding (i) a lead frame on which electric circuit elements and/or optical circuit elements are mounted, (ii) and/or a circuit board on which electric circuit elements and/or optical circuit elements are mounted (hereinafter referred to as xe2x80x9clead frame or the likexe2x80x9d), the terminals of the lead frame or the like being exposed outside from the molded body.
In the electric circuit unit according to the present invention, the module incorporating electric or optical circuit elements is bonded to and between the circuit boards such that the circuit boards are electrically or optically connected to each other. This achieves high-density mounting, enabling the electric circuit unit to be made in a compact design.
It was not possible to provide a conventional connector for connecting the circuit boards to one another with an optical connection function. According to the present invention, however, the optical connection can also be made.
Examples of the electric circuit element include an integrated circuit, an individual semiconductor element, a capacitor, a resistor, an inductance, a filter, a switch and the like.
Examples of the optical circuit element include a light emitting element, a light receiving element, a Si platform, a lens, a waveguide, an optical fiber, an optical filter, a photonic crystal and the like.
The module maybe provided, on its end face not connected to any of the circuit boards, with an electric or optical connection structure for connecting the module to an external device. According to the arrangement above-mentioned, the module can directly be connected to an external device. There may be disposed a plurality of external-device connection structures.
The circuit boards are disposed at an optional angle, and may be disposed for example at an angle 0xc2x0 (parallel) or 90xc2x0 (orthogonal) with respect to one another. When the circuit boards are disposed at an angle 0xc2x0, the circuit boards are horizontally disposed and connected to one another with modules.
The characteristic impedance of the electric signal wirings inside of the module can be set to 50xcexa9 by adjusting parameters of the wirings (signal lines, ground lines, insulating material) or the like.
The following description will discuss specific arrangements of the present invention with reference to the attached drawings.